This invention relates to inserting a probe into a biological subject, and more particularly to inserting a probe into a difficult to reach area in a biological subject.
A probe is a small object that can be inserted into a biological subject. Probes perform a variety functions. For example, some probes detect energy in a target area of a biological subject. Other probes deliver energy to a target area. Leads including electrodes inserted into a human heart provide a conductive path to the heart. Leads including electrodes inserted into a human brain provide a conductive path to the brain. Fiber optic cables inserted into a biological subject provide an optical path for viewing or ablating a target area.
One method of inserting a probe into a biological subject includes inserting a straight tube or cannula into the biological subject. The distal end of the cannula is positioned near a target area. A probe is inserted into the cannula and pushed into the target area. Finally, the cannula is removed from the biological subject leaving the inserted probe positioned in the target area.
This method is useful for inserting a probe into a target area that lies on an unobstructed straight line path from the surface of the biological subject to the target area. Unfortunately, this method is not suitable for inserting a probe into a target area in which the straight line path includes biological structures that are damaged by the insertion of a cannula or in which the target""s orientation is different than the preferred trajectory of the probe.
Many areas of interest in a biological subject are located in the subject such that a straight line path from the surface of the subject passes through a biological structure that would be damaged by the insertion of the cannula. For example, the straight line path from the surface of a human subject that passes through the subthalamic nucleus along its longitudinal axis includes the lower forehead and occipital orbit. Aside from cosmetic reasons, many critical structures lie along the path and would damaged by an incision.
For these and other reasons there is a need for the present invention.
The present invention provides a device for deflecting a probe. The device includes an outer tube having an opening at or near the distal end and an inner tube capable of sliding within the outer tube. The inner tube has material properties such that as the inner tube slides beyond the distal end of the outer tube, the inner tube follows a desired travel path. The distal end of the outer tube may be designed to encourage deflection of the inner tube as the inner tube moves beyond the distal end of the outer tube. This and many other embodiments are described in more detail below.